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This video serie shows the basic workflow with particle fluids, from sand to multiple interacting fluids, hope you will like them.
I warn that this videos are made with an older version of Particle Fluids patch so the GUI and some internals have changed, and the results now are much more better thanks to Jahka feedback.
but still they worth it 😉

Special thanks to Blendiac and WhifeofBlendiac for bringing those videos 🙂

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Here are basic functionalities of the particle fluids.
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Blender Particle Fluids integrate into the existent powerful Blender particle system a fluid simulation tool that allows a wide range of fluids types, from steam to water to goo, slime and giggly fluids.
The particle fluids inherit all the goodies of the base particle system, like baked simulations, scripting, etc.
In future releases it will also include meshing particles .
Blender Fluid Particles uses a boundless interpolation technique to sample the fluids body called SPH (Smoothed Particle Hydrodynamics)
Each particle can carry any fluid property: density, pressure, temperature, color, etc.

Smoothing radius is the most important parameter in the simulator, it controls the influence of each particle, and determines the performance and the type of the simulated fluid: for small fluid scales (droplets, tiny water) use a relatively big smoothing radius (1.0) and for big scales fluids (sand, sea, rivers) use a small one (0.2-0.1).

Masscontrols the amount of fluid matter that each particle represents, it is important for multifluid interactions (denser and lighter fluids) and also for simulating different fluid scale with the same particle amount.

Viscosity controls the movement of the fluid, making it more goo like and also more stable: it is a factor that dampens the relative velocity of each particle.

Particle damping is a stabilization factor and controsl the absolute particle velocity: when a simulation seems to be out of control try to increase it or play with viscosity. It differs from viscosity because the second damps the relative particle speed.

Stiffness controls the surface tension on an external level, but internally is an attraction force in each particle smoothing radius. For small scale fluids use high stiffness values (1.0) and for large scale fluids use low to none ones.

Repulsion factorhas the opposite effect as stiffness factor, it repels each particle from its neighbours to maintain an Equilibrium.

Collider dampingaffects the bouncing of the particle in the collision event, the more collider damping the more energy the particle will loose the particle and consequently possibly get stick to the collider surface (not enough remaining energy to cancel the attraction force).

Collider particle friction affects the particle velocity as it travels over the collision object, increase its value to get realistic slipping liquid effects.

Rest density is an important parameter that sets the density at which particles will try to maintain under a zero force field or rest state. Visually it controls the relative distances where particles will be settled.

Tweak parameter is a time step tweak for the simulation, if a sim set up goes unstable first try to lower the time step by setting a fractional tweak. SPH simulators are not unconditionally stable: they are stable only for relative small time steps, that’s the reason why increasing the particle count without adjusting the rest of the parameters could lead to exploding simulations 🙂 The good news is that always will be a set of parameters that will make a desired simulation stable.The particle integrator is the function that actually advances particles over time, they feature more fast and stable simulation, so correctly choosing the appropriate integrator is crucial. In general Midpoint is the most stable while Euler is the fastest and Verlet is more suited for fluid behaviors.

For Goo like fluids Spring is very important, this is a force among pairs of particles that try to maintain them to a fixed distance, the rest length.

Therest length is the distance particles will try to maintain with a force proportional to the spring factor.

Brownian adds a random movement to the particles, useful for small scale fluids or crazy FX’s.

Collider stickiness controls the force factor that try to stick particles to the collider surface, this is great for slipping fluids.Square viscosity is a second order viscosity factor, used for advanced fluid for enhancing viscous behaviour.

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Particles fluids can be currently rendered as billboards, simple dots, halos, instanced objects and volumetric distorted spheres in the pointdensity texture type.

In the future they can be rendered as fluid isosurfaces.

There’re plenty of ways in particle fluids for interactions and advanced setups, and combinations of the parameters lead to non-linear behaviours so they are not the simply sum of
effects. If you want to master particle fluids a good amount of experimentation is advised as well as a basic understanding of particle fluids theory.

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Thanks to Jahka review and advices I have corrected the particle fluids patch and have simplified it for better integration. Also I have discovered and solved an important bug in the multi-fluids interaction that caused strange behaviors in fluids.

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Just a quick update:
I’m working with Jahka refining the final patch, thanks to its feedback abd
the users feedback I will modify several things in the final patch, like default values and remove some small things that are in future particle system design roadmap.
Next week when Blendiac and WhifeofBlendiac return home they will upload
several very interesting high resolution screencasts I have made on some use cases of particle fluids.

Including a very interesting one using particle fluids to simulate sand
(high number of small solid points that interact with its closest neighbours) of 100k particles, at near 1 fps simulation.

Cheers to all
Farsthary

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WOW! I’m really speechless: this monday, Blendiac and WifeofBlendiac arrived! Last time we saw it was a year ago, but time flies 😉
We are having some great times together, and I’m learning a lot from them.
I want to thank everyone who has contributed to make this possible, I take you all into account, I wish I had more connectivity in order to personally thank everyone but sadly even for posting this I had to wait till today because the website partially loaded and connection speed and bandwidth is nearly non existent.
But that won’t stop me to appreciate every tiny bit of effort that the Blender community put on me, that definitively compels me to give more of myself 🙂
From sponsorship support (that is huge for me 🙂 ) to students support (oh, those are very appreciated because it means a lot of sacrifices for them) all around the world that’s something really beautiful.
The fresh papers and Blender videos I have received represent also an incredible amount of resources.
Blendiacs are very nice friends and I bet they’re like the rest of the huge Blender community: altruism, friendship, humbleness are the first words that came to my mind thinking of them and all of you 🙂
Anything that I can accomplish pales compare to this gesture. This feeling of family is what makes Blender community deserves the best 3D software ever 😉

I will take the opportunity and send you via Blendiac several high quality video timelapses of particle fluids, they’re very needed 🙂